Thanks, GSM. I think I can answer the question about why some messages are treated as spam.
Email systems have intelligent systems built into them that try to learn from an account holder’s behaviour. We can set our own rules for what we want to see and what we don’t but the system does sometimes set up its own rules.
If you have a bulk clear out of emails from a particulary sender, it will recognise this and may assume that you don’t want to see anything further from that sender.
For example, order something from Amazon and you will receive an email confirmation of the order, an email when the order has been dispatched and an email when the order has been delivered. All this is recorded in the customer’s Amazon account so the emails can be deleted but if you are a frequent customer and don’t keep on top of this, the number of emails can build up.
The account holder then decides to do some housekeeping and does a bulk delete of every email from Amazon. The system recognises this and may assume the account holder no longer wants to hear from the company. It will send future emails to spam or the delete folder where they are usually deleted permanently between 10 and 30 days later.
If you see this happening, you need to to delete a rule or filter that the system has set up and create your own. In Gmail, it’s the cog wheel, See All Settings, Filters and Blocked Addresses, Create a New Filter. In Hotmail you can find this under the three dots along the top menu depending on what layout you have, then Rules.